He heads into the friendly confines of Michigan on Feb. 28, where his father was governor, but he’s fighting battles on two fronts. Santorum continued to call Romney’s conservative roots into question, while President Obama’s camp criticized Romney for pandering to the far right.

“There’s no doubt Romney has rushed to check off every box on the tea party’s litmus test,” Obama campaign spokesman Ben LaBolt told CNN. “But the same lack of trust Romney is facing from many conservatives would be amplified in a general election across the ideological spectrum, because he has taken both sides of so many key issues and said anything to please whatever political audience he is courting.”

Santorum told CNN that Romney somehow “rigged” the CPAC straw poll.

“For years, Ron Paul’s won those because he just trucks in a lot of people, pays for their ticket, and they come in and vote and then they leave,” Santorum said, according to the LA Times. “I don’t try to rig straw polls.”

When pressed, Santorum offered no supporting evidence.

“Well, you have to talk to the Romney campaign,” he said. “We’ve heard all sorts of things.”

Romney’s camp brushed off the criticism, and instead reminded everyone of his victories.

“Rick Santorum has a history of making statements that aren’t grounded in the truth,” spokeswoman Andrea Saul told the Times. “Yesterday, Mitt Romney won the CPAC straw poll and won a separate nationwide survey of conservatives conducted by CPAC organizers. Also, Mitt Romney won the Maine caucuses.”

Depending on your perspective, Romney is either the candidate everyone is afraid of, or sailing a sinking ship.

Santorum is getting additional high-profile support from Rush Limbaugh and Sarah Palin, both of whom fixated on Romney’s “severely conservative” speech on Saturday at CPAC. Limbaugh said he’s never heard anyone refer to themselves as “severely conservative.”

Palin told Fox News Sunday there are many questions lingering over Romney’s campaign.

“I am not convinced, and I do not think the majority of GOP and independent voters are convinced,” she said, the Washington Post reported.